Permeability tuning mechanism



April 4, 1950 Filed Feb. 28, 1947 W. A. SCHAPER s sums-Sum 1 15 17 lei \NVENTOR. MAL/AM ,4. 5, 52.

April 4, 1950 w. A. SCHAPER PERMEABILITY TUNING MECHANISM 3 Sheets Sheet 2 Filed Feb. 28, 1947 April 4, 9 w. A. SCHAPER 2,503,220 PERMEABIIIIZLITY TUNING mzcmmsu Filed Feb. 28, 1947 a Sheets-Sheet s ig .56 5a .55

INVENTOR. W/LL/HMA.-5CHAPEE Patented Apr. 4, 1950 Application February 28, 1947, Serial No. 781,481 0 Claims. (Cl. 7l-10.7) I

The invention pertains to an improved construction oi permeability tuning mechanisms by which the movement 01' a ierro-magnetic core or cores relatively to a corresponding inductance coil or coils is assured to vary the inductance oi the coil or coils as required for permeability tuning purposes, which construction at the same time provides a minimum of bulk for the casing of the tuning mechanism, consistent with the proper operation of the inductance coil or coils.

The invention includes a casing having a U- shaped sheet metal member comprising the bottom and end walls of the casing, and parallel side walls of sheet insulating material having notched ends cooperating with notches in the end walls 0! the casing to interlock the parts and hold the side walls in parallel position. The mechanism also includes an operating shaft extending between the side walls and having on its end portions adJacent the side walls, drums to which flexible bands are secured, said bands also being connected with a cross-head structure movable longitudinally of the side walls by rotation of the shaft. The cross-head structure includes a cross member oi insulating. material extending transversely oi the side walls, connected at its ends with side members extending parallel with the side walls of the casing, and having shoes for sliding engagement with the side walls to retain the cross-head side members in parallelism with the side walls as the cross-head structure is moved from one position to another relatively to the casing side walls. As a result oi positively driving each of the cross-head side members from the rotary shaft by means of the flexible hands referred to, equal movements in the same direction are imparted to the cross-head side members for any given rotary movement or the shaft, and as a result, the transverse member of the cross-head maintains a constant angle with the casing side walls for all of its positions resulting from opera.- tion'of said shaft. The cross-head side members are preferably rigidly connected with the transverse member of the cross-head at substantially right angles and this assists in maintaining the transverse member of the cross-head at a constant angle to the side walls of the casing for all positions of the cross-head resulting from opera: tion of the shaft. Coil forms are suitably supported in the casing and are preferably parallel with each other and with the side walls of the casing, and term-magnetic cores contained in said coil forms are connected with the transverse member of the cross-head so that said coreshave 2 qual movementsimpartedtotheminthesame direction for any rotary movement of the shalt. The object or the invention is to construct a are compact. simple in construction, positive and accurate in operation, and inexpensive to manui'acture.

so in Fig. 5 being din'erent from the corresponding details shown in Fig. 1;

Fig. 6 shows in side elevation the structure illustrated in Fig. 5;

Fig. 7 shows in vertical longitudinal sectional g view the structure illustrated in Fig. 5, taken along the line 1-1 in Pig. 5;

Fig. 8 is a vertical sectional view of part of the structure shown in Fig. 6, taken along the line H in Fig. 6;

4o P'igJisaverticalsectionalviewoiapu'tot asand'l;

Fig. 11 is a plan view of the mounting mechanism shown in If'ig. 10;

Fig. 12 showsinaviewsimilartol 'ig. 7 amodiiication of the structure there illustrated, by

50 which coil forms are supported in two horizontal planes one above and spaced from the other and by which the transverse member oi the cross-head is vertically extended for connection with the movable term-magnetic cores in the upp r plane to of the coil forms, as well as for connection with the same horizontal plane.

throughout'the ssverel vim the fem-magnetic cores in the lower plane of said coil forms. and p Fig. 13 shows in a view similar to Ill. 1. an extended form of the construction illustrated in Ila. i, by which more thentwo tuning units may bemountedinthe semecesinginsubstentielly to' si'miler perts Similar immei'els refer bers II and II from movement away irom perellelism with the side walls I and I.

Each of the crow-heed side members is provided as illustrated for the side member II in 1'13. 2 with notches iI' and II for engagement by portions of the flexible bands ii and It.

which bends may consist of cord, flexible wire through seid side wells to support drums-.1 end a I which'ere rigidly secured to-the sheit adiecent the outer surface ofthe said side wells. The end portionsofthesidewellselsosuliport ediecent their outer eurfecea'idlerwheels I end ilinlinewitbthedrumslendlrespectively,

end flexible bends il end I! extend around the idler wheels I and II respectively. and are also connected with the corresponding drums I end I.

Asshowninl'igsJendLtheupperedgesof thesidewallslendlereinline withtbeupper edges of the end wells I and I. and said side wells are substantially narrower vertically than said end walls, ieerins e mbstentiel spece betweentheloweredgeofeechsidewall endthe innersinfeceofthebottomweill. htrensverse member it of sheet insulating material ismounted to extend at substantially right angles with the side wells I end I end in a vertical plene.sothetitrestsetitslowcredgeonthev bottom wall I and extends at its end portions under end slightly beyond the outer surfaces ofv the side walls I end I. The projecting ends of the transverse member. II are rigidly secured for'the relation of the perts shownin Figs. 1, 2 end 4, with the left-hand ends of the cross-head side members II and llwhich are preferably of sheet material and disposed in vertical planes perellei with and ediacent the outer surfaces of the side walls I and I. respectively. The crossheed side members II end II are preferable mode of insulating materiel end are provided with toneues extending through corresponding notches in the transverse member II the perts ere in this postion by-suitebl'e adhesive. As e of the construction described. the left-hand ends of the. side members it and II are restricted against vertical movement by the bottom well I end the sliding engagement of the member I! with the lower edges of the side walls land I. The other ends of the members I I end II are provided with slidin shoes as iliustre'tedfor the sidemember "in Pig. 2st II. each of these; shoes comprisinsve niece of sheet metal formed as more clearly shown in Pig. 3 in interlock with the side member II and extend therefrom under' the side well I inside of which. said shoell with an un-tumed flan e l1, e. of the -shoe'being provided outside or the upturned flange II, so that the den i! end lI restreintheright-hendendsofthcsidememor equivalent materiel. As shown in Fig. 2, e

flrst portion of the flexible band It extends from the drum I around the idler wheel iI and'is "connected at its end with the side member II wet the notch II, and the remaining portion lid of the flexible band extends from the lower porizion oi the drum I for engagement with the notch II in the side member II, a suitable spring Ia being mounted in the drum I to maintain e desired tension on the parts of the flexible bendl 2, Ila. As a result of the construction described, rotary movement of the shaft I imparts movement to the transverse member II of the cross-head to the left or to the right, according to the direction of movement of the shaft, end bysuch shaft movement in one direction, the transverse member it may be moved nearly or quite into engagement with the end wall I, and

by' reverse movement of the shaft I, the righthand ends of the side members It and II may be brought nearly or quite into ensagement'with theend wall 2; Bearing in mind that the side members II and II need be no longer than required for mechanical considerations to insure the holding of the transverse member II at e constant angle to the side walls I and I, it will be observed that the described construction of cross-head, and the relation thereto of the flexible bands II and it, produces a casing structure which is most compact in the direction of the length of the side walls ,of the casing, for any required movement in the direction of the side walls oi'the transverse member II. bearing in mind that the form-magnetic cores below described as operated by the transverse member II must have a certain length to perform their functionsi and the result of the structure is as illustratedin Fig. 4, to make the length of the casing substantially twice the length of the coil form or coil forms constituting a part of the tuning v mechanism.

As shown in Figs. 1 and 4; a coil form 2! is supported in horizontal position parallel with the side walls of the casing by a mounting structure comprising sheet insulating material bent to channel formation as shown at 22, so that the edge portions of said supporting structure rest on the bottom wall I, a part of the bottom wall being bent upwardly at Ia to clamp the right-hand lowe edge portion of said supporting structure to the end wall 2, and the other lower edge portion of said supporting structure being provided with a tongue lid extending through a corresponding opening in the bottom wall 3 and held in that position by suitable adhesives. The supporting structure .22 is limited in height to that required for proper operation of the coil or coils supported by the coil form 2|, and the shaft I is given: a vertical location relatively to the side walls I and 5 such that it is Just above and slight- 1y out of contact with the coil form support 22, thereby reducing the vertical height of the casing .of the tuning mechanism to the minimum amount permitted by proper operation of the coils on the 'coil forms. The tuning mechanism described is known as permeability tuning mechanism, by

which term-magnetic cores are provided in the or the lrindasoaaao 33 and 21 respectively, with the transverse member l3 of the cross-head, as a result of which, operation of the cross-head as described, simultaneously moves the cores 24 and 23 corresponding amounts in the same direction relatively to the coil i'orms 2| and 23, for any givenv operation oi theshaft.

' Inductance windings are not shown on the coil forms illustrated, since their use in connection with the coil forms is well known and understood, and for the further reason that the present invention is not concerned with the electrical operation of the apparatus, but with the structure by which compact and effective tuning mechanisms are produced. As is well known, variable inductance mechanisms of the kind described are frequently employed as the tuning means for resonant circuits involving the use of ilxed capacitors, and where the mechanism of the invention is used for that purpose, the coil form support 23 forms a convenient support also for capacitors 23 and 23 for use respectively with inductance coils supported by the coil forms II and 33. In many cases it is desired in radio receivers to use two permeability tuning devices in cooperation with each other, for example as an ant nna tuner and also as an oscillator tuner, and for thi purposethe double unit illustrated in Figs. 1, 2'and 4 is well adapted. The invention, however, is not restricted to the use of any particular number of tuning units in the entire mechanism mounted in a single case, since the compactness of the structure and the efllcacy of its operation are available equally where any number of tuning devices are mounted in the same casing.

In the modified construction of the tuning mechanism illustrated in Figs. 5- 11 inclusive, the casing includes end walls 33 and 3| and a bottom wall 32 of sheet metal bent into a U-shape and having interlocking engagement with the ends of the side walls 33 and 34 which are of insulating sheet material having notched ends engagin i corresponding no ches in the end alls to eflectively secure the side walls to the end walls. With this construction, an operating shaft 35 extends between and through the side walls 33 and 34 and transversely of said side walls, but in this case said shaft is located in the lower portion of the casing instead of being located in the upper portion thereof as shown in Figs. 1, 2 and 4. With the construction illustrated in Figs. 5-7 inclusive, the shaft 35 has secured to its ends ad acent the outer surfaces of the side walls 37 and 34, drums 33 and 31 in line with idler wheels 33 and 39 respectively, which are supported by side walls 33 and 34. Flexible bands 43 and 4| extend around the drums 36 and 31 and the idler wheels 33 and 33 respectively, to operate the cross-head of the structure by rotary movement of the shaft 35 in substantially the manner described above for the construction illustrated in Figs. 1, 2 and 4. The cross-head shown in Figs. 5, 6 and '1 includes a transverse member 43 of sheet insulating material rigidly connected at its end portions with sheet-metal shoes 43 and 44 which 3| coil form '46. In the other end of the bent mem- 6 have an angular cross section in sliding engage-'- ment with the upper edges of the side walls 33 and 34. As shown in Figs. 8 and 9, the lower portion oi the sliding shoe 44 is bent outwardly away from the side wall 34 as indicated at 44a and 44b. To facilitate connecting the flexible band 4| with said sliding shoe, said band cons sts oi two portions Ma and 41b,'the portion 4 la extending from the drum 31 around the idler wheel 33 and to the left-hand end of the shoe 44 where said band is' held in engagement with said shoe by a projecting lug 44c of said'shoe, and the band portion 4 lb extends from the drum 31 to the other end of the shoe 44 where it is connected with said shoe'by means of a notch 44d at the' end of said shoe. The shoe 43 is similarly formed and similarly connected with the band 43 which comprises similar portions connected with the drum 36 and with the shoe 43 as described for the band 4| and shoe 44. The transverse member 42 has a length making it a sliding fit between the side walls 33 and 34 and as a result of the shoes 43 and 44 extending adjacent the outer surfaces of the side walls 33 and 34, displacement oi' the cross-head in a horizontal plane relatively to the side walls is prevented.

As shown in Fig. 6, the side wall 34 is provided with a slot 45 parallel with the upper edge of said side wall, to receive bent lugs 44c and 44! extending into the slot 45 from the shoe 44, which lugs together with the engagement of the upper edge of the side wall by the shoe 44, restrain the crosshead from vertical displacement relatively to the side wall. The shoe 43 and side wall 33 are formed in a similar manner to that described for the shoe 44 and side wall 34 and have similar engagement with and relation to each other, as a result of which the cross-head is supported for longitudinal sliding movement on the side walls a 33 and 34 and restrained from displacement relatively to the side walls in all directions, the only movement of the cross-head permitted by the construction being a slidin longitudinal move ment relatively to the side walls 33 and 34 produced by the action of the flexible bands 43 and 4| by imparting turn ng movement to the shaft 35. With the construction shown in Figs. 5, 6 and 7, the side walls 33 and 34 are of less width than the height of the end walls 30 and 3|, as a result of which. with the lower edges of the side walls 33 and 34 resting on the bottom wall 32 of the casing, a clearance is provided above the upper edges of the side walls and below the upper edges of the end walls within which the cross-head structure may move without interfering with other parts that may be adjacent the tuning mechanism in a complete assembly of apparatus.

As shown in Fig. '1, provision is made in the casing to support one or more coil forms 43 in horizontal position parallel with the side walls 33 and 34, above the shaft 33, instead of locating the coil forms below the operating shaft as shown in Figs. 1, 2 and 4. Each of the coil iorms 43 iilustrated in Figs. 5 and 7 is provided with a supporting structure more clearly shown in Figs. 10 and 11, which includes a strip of sheet insulating material 41 bent into a U-shape and provided at its right-hand ends with a strip of sheet insulating material 43 extending between the righthand end portions of the bent strip 41 and having interlocked and notched engagement with said end portions and secured in place preferably by suitable adhesive, the strip 43 having an aperture therein supporting the right-hand end of the ber 41, a flat piece sheet insulating material 43 is disposed which extends through and above and below the bent member 41, and which has interlocking notched engagement with the member 41 to hold the parts in proper position by means preferably of suitable adhesive. The member 49 is provided with an aperture supporting the lefthand end of the coil form 48, so that bysuitably supporting the member 49 the coil form is given definite support in the casing of the tuning mechanism. As shown in Fig. '7, the upper edge of the member 41 "of each of the coil form supporting structures is in the horizontal plane of the upper edges of the side walls 33 and 34, and the member 43, extends below the member 41 sufliciently to engage and be supported by the bottom wall 32 of the casing. The member 49 extends above the member 41 nearly to the upper edge of the end wall 30 and bent tongues 30a and 32a formed from the end wall 30 and bottom wall 32, engage the upper and lower edges of the member 43 to positively hold the coil form support in proper position. Each of the coil forms 46 is preferably provided with its own supporting structure independently of the other coil forms.

For the purp e of securing a variation in inductance of the inductance windings mounted on coil forms 46, each of said coil forms is provided with a ferro-magnetic core 50 movable axially in said coil form and connected by a slender metal rod 51, with the transverse member 42 of the cross-head, so that by rotary movement of the shaft 35 all of the term-magnetic cores oi. the tuning mechanism are simultaneously moved in the same direction and to the same extent, depending upon the amount of rotary movement of said shaft. Where the inductance windings mounted on the coil forms 46 are used as parts of tuned resonant circuits, tuning capacitors may conveniently be mounted on the end wall 3! as illustrated at 52 and 53. To prevent lateral displacement of the mid-portions of the side walls 33 and 34, the bottom wall 32 preferably has formed from it, tongues 32b engaging opposite sides of the lower portions of the side walls as indicated.

The construction illustrated in Figs. 5-11 inclusive has all of the advantages described in connection with Figs. 1,2 and 4 and operates in substantially the same manner to secure substantially the same results.

The construction of tuning mechanism thus far described, is adapted for use where one or more coll forms and tuning cores are used in the tuning mechanism in a single horizontal plane. In some cases it is desired to simultaneously operate tuning units located in two horizontal planes, one above the other, either to avoid the undue width of the casing resulting from the number of units employed or because of desiring to have the height of the mechanism as a whole more nearly equal to its width, as may be desired in some assemblies of apparatus. The construction illustrated in Figs. 5, 6 and 7 is readily adapted with small modification, to simultaneously operate tuning units in a plurality of horizontal planes one above the other and with a plurality of said units in each of said planes as illustrated in Fig. 12. With this construction, the casing of the mechanism is the same as described in connection with Figs. 5, 6 and 7 and the crosshead construction is operated in the same manner as there described, the only difference in connection with the cross-head construction being that the transverse member 54 is made higher manner similar to that illustrated in Figs. 10 and 11, a U-shape supporting member 58 and crossmember 39 being employed for each coil form and having the same construction and relation to the coil form as described for the members 41 and 44 in connection with Figs. 10 and 11.

with the construction of Fig. 12, the member 49 01 Figs. 10 and 11 is replaced by a similar member 60 which is extended sufllciently above the end wall 30 to support the coil form or forms 38 in the upper horizontal plane of said coil forms, the manner of supporting the members 58 from the members 80 being the same as described in connection with Figs. 10 andii tor supporting the member 41 from the member 48. With the construction of Fig. 12, the member 33 of the coil form support rests on the bottom wall 32 of the casing and is held in vertical position adjacent the end wall 30 by lugs 30a and 82a in the manner above described. For convenience in handling the coil forms and their supporting structures and for mounting them in the casing, as well as for providing flexibility in the number of coil forms that may be employed in any particular case, it is preferred that each pair of coil forms 56 and 5? which are disposed one above the other, be provided with its individual supportlug-member 5!]. The coil forms 56 and El support ferro-magnetic cores 6! and 32 movable axially in said coil forms and connected by slender rods 55 and 63 with the transverse member 53 of the cross-head, as a result of which all oi the cores of the mechanism illustrated'in Fig. 12 are simultaneously moved in the same direction and to the same amount, depending on the amount of angular movement imparted to the shaft 35.

In some cases, it is desiredto use more than two tuning units in a single horizontal plane, instead of providing the structure with two of said units as shown in Fig. 1. This is readily accomplished as illustrated in Fig. 13 by expanding the structure of Fig. 1 laterally by an amount determined by the number of tuning units it is desired to mount in the same housing. In this case, the end walls 64 and 65 and thebottom wall 66 are of the same construction described in connection with Fig. 1, the only difference being that they are of greater extent laterally between the side walls 67 and 83, which side walls have the same construction as shown in Figs. 1 and 2. With the construction of Fig. 13, the transverse member 69 of the cross-head has the same construction and form of mounting as the transverse member l3 shown in Fig. 1, the only diiierence being that it is sufllciently longer than the transverse member I3 to extend between the side walls 31 and 68 in the positions they have determined by the number of tuning units employed in the casing of the tuning mechanism. All of the anally movable ferro-magnetic cores l0 employed with the structure illustrated in Fig. 13 are connected by slender rods II with the transverse member 69 for simultaneous movement in the same direction and to the same extent by angular movement of the shaft I2, depending upon the extent of said movement, in the same manner described above in connection with the apparatus shown in Figs. 1, 2 and 4. The cores 16 shown in Fig. 13 cooperate with coil forms in the same manner described in connection with Figs. 1, 2 and 4, and

said coil forms are supported in the casing of the mechanism in the same manner as above describedin connection with has. 1, 2 and 4 and may conveniently be provided with tuning capacitors It, one for each of the tuning units and supported in the same manner above described in connection with Figs. 1,2 and 4 for the capacitors "and 2!. It will at once appear that the structure illustrated in Figs. 5, 6 and i may be expanded in the same manner as illustrated in Pig. 13 for the structure shown in Fig. 1, where it is desired to employ more than two tuning units in a single horizontal plane, and at the same time use the arrangement of parts illustrated in Figs. 5, 6 and 7.

While I have shown my invention in the particular embodiments above described, it will be understood that I do not limit myself thereto as I may employ equivalents thereof without departing from the scope of the appended claims.

Having thus described my invention, what I k claim is:

1. A permeability tuning mechanism for radio purposes for moving cores axially in associated coil forms, including in combination a frame for supporting a coil form and having parallel and laterally spaced side walls, a rotatable shaft extending at right angles between said side walls, a pair of drums of the same effective diameter secured to said shaft in spaced relation. a crosshead slidably mounted for 'movement longitudinally of said side walls and extending transversely therebetween, a flexible band around each of said drums and connected with portions of said crosshead spaced apart in the direction of its movement, and a core-operating rod extending from said crosshead and in the direction of movement of said crosshead.

2. A permeability tuning mechanism for radio purposes for moving cores axially in associated coil forms, including in combination a frame for supporting a coil form and having parallel and laterally spaced side walls, a rotatable shaft extending at right angles between said side walls, a pair of drums of the same effective diameter secured to said shaft in spaced relation, a crosshead slidably mounted for movement longitudinally of said side walls and extending transversely therebetween, a flexible band around each of said drums and connnected with portions of said crosshead spaced apart in the direction of its 4. A permeability tuning mechanism for radio purpoeesformovingcoresaxiallyinassociated coil forms. including in combination a frame for supporting'a coil form and 1mm: Wallel and laterall spaced side walls, a rotatable shaft extending at right angles between said side walls.

a pair of drums of the same effective diameter secured to said shaft in spaced relation, a-crow head slidably mounted for movement longitudi naily of said side walls and extending transverselytherebetween, a flexible'band around each of said drums and connected with portions of said crosshead spaced apart in the direction of its movement, and a core-operating rod extending from said crosshead and in the direction of movement 5. A permeability tuning machanism for radio purposes for moving cores axially in associated coil forms, including in combination a frame for supporting a coil form and having parallel and laterally spaced side walls, a rotatable shaft ex-. tending at right angles between said side walls,

- a pair of drums of the'same effective diameter movement, a core-operating rod extending from said crosshead and in the direction of movement of said crosshead, and guide means in line with each of said drums and guiding the corresponding flexible band.

3. A permeability tuning mechanism for radio purposes for moving cores axially in associated coil forms, including in combination a frame for secured to said shaft in spaced relation, a cross-- head slidably mounted for movement longitudinally of said side walls and extending transversely therebetween, a flexible band around each of said drums and connected with portions of said crosshead spaced apart in the direction of its move ment, and a core-operating rod extending from said crosshead and in the direction of movement of said crosshead, said crosshead comprising side members of formed sheet metal slidably mounted onsald side walls and a. transverse member of insulating material connected at its ends with said side members, said side walls having longitudinal slots therethrough, and said side members having retaining lugs extending therefrom and into said slots.

6. A permeability tuning mechanism for radio purposes for moving cores axially in associated coil forms, including in combination a frame for supporting a coil form and having parallel and laterally spaced side walls, a rotatable shaft extending at right angles between said side walls. a pair of drums of the same effective diameter secured to said shaft in spaced relation, a crosshead slidably mounted for movement longitudinally of said side walls and extending transversely therebetween, a flexible band around each of said drums and connected with portions of said crosshead spaced apart in the direction of its movement, a core-operating rod extending from said crosshead and in the direction of movement of said crosshead, and guide means in line with each supporting a coil form and having parallel and 00 of said drums and guiding the corresponding laterally spaced side walls, a rotatable shaft exflexible band, said crosshead comprising side tending at right angles between said side walls, members of formed sheet metal slidably mounted a pair of drums of the same effective diameter secured to said shaft in spaced relation, a crosson said side walls and a transverse member of insulating material connected at its ends with head slidably mounted for movement longitudisaid side members.

nally of said side walls and extending transversely therebetween, a flexible band around each of said drums and connected with portions of said crosshead spaced apart in the direction of its movement, a core-operating rod atending from said 7.

crosshead and in the direction of movement of said crosshead, and guide means in line with each of said drums and guiding the corresponding flexible band, said guide means comprising idler rollers supported by said side walls.

aaoaaao therebetween, a flexible band around each of said drums and conneotedwith portions of said crosshead spaced apart in the direction of its movement, a core-operating rod extending'frorm said crosshead and in the direction 01' movement of said crosshead, and guide means in line with each 01' said drums and guiding the corresponding flexible band, said crosshead comprising side members of formed sheet metal slidabl mounted on said side walls and a transverse member of insulating material connected at its ends with said side members, said side walls having longitudinal slots therethrough, and said side members having retaining lugs extending therefrom and into said 4 slots.

8. A permeability tuning mechanism for radio purposes for moving cores axially in associated coll forms, including in combination a frame for supporting a coil form and having parallel and laterally spaced side walls, a rotatable shaft extending at right angles between said side walls, a pair of drums of the same efl'ective diameter secured, to said shaft in spaced relation, 9, crosshead slidably mounted for movement longitudinally of said side walls and extending transversely therebetween, a flexible band around each of said drums and connected with portions of said crosshead spaced apart in the direction of its movement, a core-operating rod extending from said crosshead and in the direction of movement of said crosshead, and guide means in line with each of said drums and guiding the corresponding flexible band, said guide means comprising idler rollers supported by said side walls, said crosshead comprising side members of formed sheet 35 2,038,281

metal slidably mounted on said side walls and a transverse member of insulating material connected at its ends with said side members.

9. A permeability Purposes for moving cores axially in associated coil forms, including in combination a frame for supporting a coil form and having parallel and laterally spaced side walls, a rotatable shaft extending at right angles between said side walls, a pair of drums of the same efl'ective diameter secured to said shaft in spaced relation, a crosshead slidably mounted for movement longitudinally of said side walls and extending transversely therebetween, a flexible band around each of said drums and connected with portions of aid crosshead spaced apart in the direction of its movement, a core-operating rod extending from said crosshead and in the direction of movement of said crosshead, and guide means in line with each of said drums and guiding the corresponding flexible band, said guide means comprising idler rollers supported by said side walls, said crosshead comprising side members of formed sheet metal slidably mounted on said side wallsand a transverse member of insulating material connected at its ends with said side members, said side walls having longitudinal slots therethrough, and said side members having retaining lugs extending therefrom and into said slots.

WILLIAM A. SCHAPER.

REFERENCES crrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Gustafson Apr. 21, 1936 2,217,984 Kirk Oct. 15, 1940 2,286,283 Kirk June 16, 1942 2,338,134 Sands Jan. 4, 1944 timing mechanism for radio 

